Question

The thermo e.m.f. of a thermocouple is given by $E=2164t-6.2t^2$. The neutral temperature and a temperature of inversion are

• A. 349, 174.5
• B. 174.5, 349
• C. 349, 698
• D. 698, 349

Answer 1

The correct option is B 174.5, 349

Given, $E=2164t-6.2t^2$
At neutral temperature $t_n,\frac{dE}{dt}=0$
$\Rightarrow 2164-6.2\times 2t_n=0$

$\Rightarrow t_n=\frac{2164}{12.4}=174.5$

At inversion temperature $t_i,E=0$

$\Rightarrow 2164t_i=6.2t_i^2=0$

$\Rightarrow t_i=\frac{2164}{6.2}=349$